Avoid camera access popup when pausing/restarting camera

[luogu]

Pause & Validate

Using the Pause function, in fact, the camera is still constantly recognizing barcodes or QR codes, isn't it?

[gruhn]

It shouldn't. Pausing should fully disconnect the camera. In desktop Chrome for example you know the camera is running if there is a red "recording" dot over the tab icon. In iOS there is a little green dot in the top right, next to the battery status.

You can still see an image when the component is paused. This is possible because the component captures the last camera frame before disconnecting and renders it to a canvas.

[luogu]

Pause
Can we just pause the barcode parsing instead of pausing the video stream, otherwise the phone will prompt 'Camera usage permission enabled' every time,

[gruhn]

It doesn't on most devices as far as I can tell. What device/OS are you using?

[luogu]

iphone 12 + chrome

[gruhn]

Ah you mean that you keep getting the confirmation popup. I thought you have to keep confirming camera access permission. I agree that is somewhat annoying. Previously the camera would not get disconnected when pausing. This can be done by simply invoking the pause function of a video element. But for some reason we removed that. I have to go digging.

[luogu]

Looking forward to your update! Thank you for your ongoing work on this project.

Best regards,

[gruhn]

I found the issue that motivated this change: #24

So you get a different UX issue. There is probably a way to get the best of both worlds. But this is non-trivial, even though we used the videoElement.pause() approach before. The logic for managing the camera is subtle and easy to break. No promise that I can work on this anytime soon.

[luogu]

Do not let it continuously prompt 'Camera usage permission enabled'. For manual scanning, scanning one barcode at a time, the experience will be very good